This application claims the priority of Japanese Patent Application No. 9-39936 filed on Feb. 7, 1997, which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an image pickup apparatus for an endoscope, particularly to a structure and a fabrication method of an image pickup apparatus to be mounted on a circuit board by making at least the image pickup plane side of a solid-state image pickup device airtight.
2. Description of the Prior Art
FIGS. 8(A) and 8(B) show an assembly constituted by setting a solid-state image pickup device into a package in a conventional electronic endoscope and the assembly is used for a simultaneous endoscope. As shown in FIG. 8, a CCD (Charge Coupled Device) 1 serving as a solid-state image pickup device is stored in a box-type package (also serving as a circuit board) 2 made of ceramic or the like and a terminal G of the CCD 1 side and a terminal (pad) H of the package-2 side are connected by a bonding wire 3.
Moreover, a cover glass 4 with an air gap provided for the image pickup plane side (upper side) of the CCD 1 is bonded onto the package 2 and the package 2 is made airtight. That is, in the case of the CCD 1, a microlens and a color filter are formed on the image pickup plane, the function of the microlens is held by the air gap, and the color filter is prevented from deteriorating by the airtight state.
A terminal (pad) I connected to the terminal H is formed at the left end of the package 2 in FIG. 8(A) and a signal cable is connected to the terminal I. Thereby, it is possible to transmit a driving signal supplied to the CCD 1 and a video signal read from the CCD 1.
FIG. 9 shows the inside of the front end of an endoscope with the image pickup device assembly in FIG. 8 set in it. At the front end 5, an objective optical system 6 is set onto the cover glass 4 of the package 2 through a prism. A light guide 7 is set to the right and left of the objective optical system 6 and an action-tool passing channel 8 or the like is formed below the package 2. According to the above structure, the inside of an object to be observed is picked up by imaging the object captured by the objective optical system 6 on the pickup plane of the CCD 1.